Method for treating molds used in the art of electrotyping.



. k G.E.DUNTON. METHOD POR TREATING MOLDS USED IN THE ART OFELEGTROTYPING.-

APPLICATION FILED NOV. 14, 1913- 1411345, I Patented Sept.22,1914.

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Specification of Letters Patent.

Patented- Sept. 22, 1914..

Application filed November 143 1913'. Serial No. 800,962.

To all whom it may concern.

Be it known that I, GEoRo-n E. DUNTON, residing at. New York, inthecounty of New York and State of' New York, a citizen of the, UnitedStates, have invented; a certain new and useful Method for TreatingMolds Used in the Art of Electrotyping; and I do hereby declare thefollowing to be a full, clear, and exact descriptionpf the invention,such aswill enable others skilled in the art to. 'which it pertainstomake and use the a e. r

' My invention relates to an improved method for treating molds used inthe art of electrotyping and more particularly to the wax molds used informing electrotype plates.

invention hasfor its object. to pro- I videa method for treating molds,prior to the application of the conductive coating, whereby the grease,oil or oily substance expressed therefrom by the pressing of the fbrm orcut into the mold, in making the impression [preparatory to thedeposition of the printing shell, is absorbed,

' It further has for its object, to provide a methodfor treating molds,prior to the application ofthe conductive coating with a substance whichwill absorb the grease or oil-expressed therefrom without in any manneraffecting the material. or materials of which the mold is composed.

It still-further has for its object to provide aimethod for treatingmolds, prior to the application of the conductive coating, with asubstance which will (absorb the grease for oileXpressed-therefrom,treating the absorbed substance with a dissolving chemical substance andremoving the absorved substance and the dissolving chemical substance,from the mold by washingdor rinsing thesame with water or other fiui Thematerial of. which the molds are formed for the production of printingplates.

or} surfaces in the el'ectrotyping art is generally beeswax, ozoceritewax or like substance which contain an appreciable percentage of grease,oil or oily substance in its composition. In beeswax the grease, oil-oroily substance is due to the presence of palmitin and inozocerite-waxmineral wax, it is due to thepresence of petroleum,

In the; producing of printing plates or other printing surfaces, toformperfect reproductions of the originals from which the molds are madein the art of electrotyping it is of the utmost importance that themolds be. treated toeliminate or free them from all grease, oil .or oilysubstances, prior to the application of. the conductive coating, as anytreatment for the removal of the grease, oil or. oily substances towhich the mold may be subjected subsequent tothe application of the.conductive coating will result inthe contamination, deterioration anddestruction of the conductive coating.

When making an impression in a wax or other similar mold, preparatory tothe deposltlon of; the printing shell, the desired form or cut ispressedor forced into the surface of the mold, which causes any grease,oil or oily substance contained therein .to be pressed'or forced out andform a thin coating or film on the face of the mold and said coating orfilm is exceedingly troublesome to the electrotyper, as it causesimperfect and; faulty reproductions, especially in the case where theso-called half tone illustrations are, being made, which are composed ofa collectionofvery fine, minute dots, or in duplicating of-color plateswhere three or four, or even. more, prifitings are necessary the leastvariation from the original plate, such as the filling up of the dots orminute indentations made in the wax mold would result in a thickening ofthe duplicate or reproduction and instead of having a well 'd'efinedflat printing surface the points would vbe rounded and lacking in heightfrom one half to one fourth of the original whichwould utterly ruin theplate.

Referring to the drawing Which shows one form of apparatus forpractising or carrying out my method, Figure 1 is a longitudinalsectional'view. Fig. 2 a detail sectional view of the sprinkler. Fig. 3shows an electrotype halftone in section. Fig. 4; shows a section of animperfect electrotype taken-from the half tone shown in Fig. 1. Fig. 5shows a section of a perfectly reproduced electrotype. Fig. 6 shows aprint from Fig. 5. Fig. 7'shows a print from Fig. 4.

Figs. 3 and 4 show an electrotype and Fig. 7 print taken therefrom,before being treated by my method, and Figs. 5 and 6 show an electrotypeand .print therefrom, respectivel after treatment by my method.

In the rawings in which like reference characters denote likepartsthroughout the several views,-l represents a tank having an inclinedfalse bottom 2 which terminates at a point 3 short of one end'of thetankand forms a well 4. a

The false "bottom 2 is adapted to receive a removable frame5 upon whichthe mold'to be treated is designed to be placed and 6 is a pump, of anydesired pattern, which is connected by means of a siphon suction plipe 7to the well 4 and is provided wit a flexible discharge pipe or hose 8which connects with a sprinkler head 9 extending downwardly into thetank, and directly over the mold, and is carried or mounted on aslidable frame 10 which travels on traverse screw 11- operated by anysuitable means and said sprinkler head sprays the entire mold.

In practisin or carrying out my method of treating mo ds usedin the artof electrotyping I form a mold in the usual manner, by pouring meltedmolding composition composed largely of ozocerite wax overthin sheets ofmetal placed on a suitable table and allow the same to become firm, setor hard by the cooling of the wax, then slice a thin layer or shavingfrom the surface of the wax to provide an even,-smooth surface for themold throughout the impression area.

I The form or cut is preparedin the usual manner by being planed down toinsure an even surface, then washed with some detergent to remove anyprinting ink or other substance which may have adhered to the surface ofthe form or, the indentures therein, all excess fluid absorbed orremoved and the; form dried by being briskly rubbed with a moderatelystiff brush, after which it is brushed over very lightly with a mix tureof graphite and. lam black, as is also the surface of the wax, thisgraphite prevents the form from sticking in the wax, all the surplusmaterial is shaken out of the form and any that remains is carefullyremoved with a soft brush.

' Theform thus prepared is placed on a slidable bed of a molding pressand the mold placed carefully over the surfacewith the smooth powderedwax surface restin on the form, both are moved by the slidai into themolding press, pressure is applied which presses or forces the form.intothe wax mold to the predetermined depth desired by the operator'ofthe press, the pressure is released, the slidable bedwithdrawn from thepress and the mold carefully de tached from the form and-removed to-thebuilders bench where it is carefully examined and if it passesinspection it is trimmed down by passing a knife over thesurface toremove any portions of wax which may *projectbeyond the surface of themold as well as the surplus wax around the edges of the impression. Anyportions which it is desued to make deeper in theplate are built up inthe usual manner. At'this stage or le bed.

point I treat the mold to remove the grease,

oil or oily substance therefrom by s rinkling or dusting it over with anabsor ing sub.-

stance, having a markedavidityfor grease, working said substance intoall the indenturesand over the surface of the mold, preferably, with afine broad surfaced brush. The absorbing substance used is an alkalineearth or carbonate of lime, calcium carbon;

'ate or precipitated chalk, having the formu:

la :CaCO,, but oxid of lime, fullers earth or alkaline earths could beused. The reason.

that Iem loy carbonate of lime is that it has certain a nities andvreactions which it is necessary to bring about to successfully removethe grease after its separation from the surface of the wax mold.

The powdered carbonate of lime is allowed to remain on the surface ofthe wax for a few moments, from three to five minutes, to insure acomplete absorption of the grease,-then the mold is treated with apickle I composed of sulfuric acid dissolved or mixed with water in theproportions of 12' ounces (fluid) of acid to each gallon of water andwhen this pickle comes in ,con-

tact with the carbonate of.lime, which has absorbed the grease from the.wax, it attacks the lime carbonate, liberating carbon ,dioxid, and actsupon the grease or. oil causing it to congeal or'thicken, whereby itfloats on the surface of the liquid and may be readily re,-

moved by washing or rinsmg the moid'or by other suitable means. I nextwashmzay the'congealed grease, floating on the surface of the liquid onthe mold, 'by subjecting the mold tothe actio'njof' a stream or jet ofwater from a pump by means of a nozzle reciprocated back and forth overthe surface of the mold and when the grease has'been entirely washedaway the mold is removed from the pumping trough and the surface driedby a blast of warm air, su any suitable means, when the mol 1s ready toreceive the conductive coating of graphite or other. metallic vpowderafter a which the re by .mold is again washed out, coated with a Vpreliminary chemically precipitated coating 4 of the desired metal andplaced in the electrolytic bath to receive the deposit ofimetal whichconstitutes the electrotype shell,

What I claim is 1.- The'method of treating molds in 2. The methodoftreating molds in '5 the art of electro ing to remove thefgreasetherefrom, consisting intreating the mold prior to the application ofthe conductive coating, to a grease absorbing substance, treating saidabsorbing substance with an acid and removing the absorbing substanceand acid.

3. The method of treating molds used in the art of electrotyping toremove the grease therefrom, consisting in treating the mold prior tothe application of the conductive coating, with carbonate of lime toabsorb the grease, converting the grease absorbed carbonate of lime intosulfate of lime, freeing the grease and washing away the free greaseheld by the carbonate of lime prior to its conversion into sulfate oflime.

4. The method of treating molds used in the art of electrotypingto-remove the grease therefrom, consisting in treating the mold with agrease absorbing powder, treating the absorbed substance ,with a pickle,composed of sulfuric acid mixed with water and then removing theabsorbed grease and pickle by washing or rinsing.

5. The method of treating molds used in the art of electrotyping toremove the grease therefrom, consisting in treating the grease, whichhas been expressed from the mold, with carbonate of lime, and after thegrease has been absorbed by the carbonate of lime treating the absorbedgrease and the carbonate of lime with an acid and then removing theabsorbed grease, absorbing substance and the acid.

In testimony whereof I aflix-my signature in the presence of twowitnesses.

GEORGE E. DUNTON.

